1. Field of the Invention
The present invention relates generally to birdhouses and similarly configured feeders, and more specifically, to the convenient repeated attachment and detachment capability of a trap gate and trigger mechanism for trapping undesirable birds for removal from such structures, and for trapping desirable birds for scientific research purposes.
2. Description of Prior Art
Various beneficial and desirable native birds, such as bluebirds and purple martins, benefit from artificial nesting or feeding structures (bird houses and similarly constructed feeders). In North America, however, undesirable non-native birds such as English sparrows often usurp such structures and often destroy the eggs, nestlings or adults of native species. Some native species, such as Mountain Bluebirds, have been threatened with extinction, in part due to this problem which exists in many parts of the world.
It is known that a trap set within such a structure to capture an undesirable bird for removal from the area is effective in keeping the structure available for native birds. Only a "live" trap is safe to use where desirable, legally protected, native birds might be accidentally captured. Such a trap is also useful to capture desirable birds for research purposes, such as banding.
A number of prior art devices are capable of trapping a bird within a birdhouse compartment. Sialia, the quarterly journal of the North American Bluebird Society, in Volume 5, Number 3, pages 100-101 (Summer 1983), describes and illustrates a pivotal gate and formed wire trip mechanism permanently mounted on an installable and removable separate panel which is then attached to the inside surface of the original entry hole panel of the birdhouse. While this trap panel, as described, is attached by hand with a wire clip, it is believed to be more conspicuous to wary birds, less conveniently portable or storable within a birdhouse, and less economical to manufacture than the present invention, due to the larger size of this prior art device resulting from its use of the separate panel.
U.S. Pat. No. 4,471,721 (Arthur E. Vail, Griggsville, Ill.) describes a pivotal gate retained by a formed wire trip mechanism, both of which are permanently mounted on a substitute entry hole panel, which is, at the time of trapping, substituted for the original entry hole panel which forms one side of the nesting compartment. This patent (U.S. Pat. No. 4,471,721) applies to features for setting the trap from the outside of the compartment, and to a feature to prevent inadvertent tripping, and to a feature for mounting the separate trap panel in temporary substitution of the original entry hole panel. This patented trap panel, as described by the inventor, is intended primarily for substituting for an original entry hole panel of similar appearance and mounting means in a sheet metal birdhouse. Thus it is likely to be relatively inconspicuous to birds and easily mounted when used in the intended application. However, as this prior art device also relies on a separate substitute trap mounting panel which aligns the moving trap parts, it is also less conveniently portable or storable than the present invention if the present invention were adapted, as is possible, to this application.
Bluebirds! by Steve Grooms and Dick Peterson, page 64 (North Word Press Inc., 1991) illustrates another pivotal gate and formed wire trip mechanism both of which are also mounted on an installable/removable substitute entry hole panel which is temporarily substituted for the original entry hole panel at the time of trapping. The bearings of the rotation of the formed wire trip mechanism are formed by holes in two plates which have been pressed into two vertical saw kerfs in the substitute entry panel. These vertical saw kerfs serve only to anchor the bearing tabs. Again, the reliance of this prior art trap on a separate substitute trap mounting panel which aligns the moving trap parts, means this trap is also believed to be more conspicuous, less conveniently portable and storable, and less economical to manufacture than the present invention, due to its possible difference in external appearance (compared with the original entry hole panel) and its larger size.
Spring-activated pivoting gate, and gravity-activated sliding door, birdhouse trapping devices are a part of the general prior art. Such devices known to the present inventor are either mounted as a substitute entry hole panel, inconveniently attached in the field by tool to the inner surface of the original entry hole panel, or hung on the original entry hole panel by a hook which passes through the original entry hole, in an area in which wary birds are especially sensitive to changes. All such devices known to the present inventor are more complex and believed to be more conspicuous to wary birds, are larger and thus less conveniently portable and storable, and are less economical to manufacture, than the present invention.
As discussed above, prior art devices are inferior to the present invention with respect to one or more of the following considerations: inconspicuousness, portability, storability, ease of attachment to a birdhouse and economy of manufacture.